Oddly enough, the NA version of Jak II (for PS2) has a Japanese language option, both for the voices and actual game text (menus, subtitles, and everything, if I remember correctly). I flipped it on a few times for laughs (because some of the Japanese voices are amusing), but it’s been a while since I’ve played it, so I’d forgotten about it til I saw this thread. Might not be the best thing for learning, but it’s something that can be switched to Japanese, and doesn’t involve region-cracking a PS2.

Yeah I think you need to change steam to Japanese, I haven’t got the game myself, but I have steam in Japanese and I have all Valve games in Japanese. So that might be the way to do things.

Eventually I was going to get around playing the new DLC for Skyrim. Though I’m thinking my English version saves wouldn’t work with the Japanese version? That would suck.